After purchasing two D750's, 24-120, 18-35, 70-300, I got tired of lugging all that weight and wanted to go back to primes for awhile especially since I generally shoot street and near-person photography.
Purchased a 35/2, 28/2.8, 50/1.4 (arriving tomorrow), and 60/2.8 all AF-D lens. They are all plenty sharp, and the colors are great. Suppose that the newer primes may be better, at least according to Dxomark, but all four lenses combined cost me under $600, which as you know is in the ballpark of a single new AF-S 1.8 prime. Also purchased a 50/1.8 G (new) and 85/1.8G (*bay). The 85 was about 1/2 price of new.
Haven't done a direct comparison between the AF-D and AF-S G lenses and probably will only do so looking at the final product and nothing scientific.
Will report and post photos after I shoot around some.
For me, there's something special about using a prime that I don't get using zooms.